Looper mechanism for sewing machines



Aug. 113, 1940.

H. HACKLANDER ET AL LOOPER MECHANISM FOR SEWING MACHINES Filed June 22, 1937 4 Sheets-Sheet 1 wm m mam M wmw m N6 T [mm T e Aug. 13, 1940. H. HACKLANDER ET AL LOOPER MECHANISM FOR SEWING MACHINES Filed Jun 22, 19:57 4 Shets-Sheet 3 wwm w E E H mw INVENTORS: 7721225 jfaeiclanalerfi Gem ya azwr (I W 4TTORNEYS.

Aug. 13, 1940. H. HACKLANDER ETAL 2,211,519

LOOPER MECHANISM FOR SEWING MACHINES Filed June 22, 1937 4 Sheets-Sheet 4 INVENTORS ifans ifdciclandara BY Gaol wig WTORNEYS 'WI TNESSES:

Patented Aug. 13, 1940 UNITED STATES LOOPER MECHANISM FOR SEWING MACHINES Hans Hacklander, Linden, N. J., and George Sauer, Berwyn, I11., assignors to Union Special Machine Company, Chicago, 111., a. corporation of Illinois Application June 22, 1937, Serial No. 149,592

16 Claims.

This invention relates to looper mechanism useful in cooperation with the needles of sewing machines to form chain stitch seams; and it has reference more especially to looper mechanism useful in sewing machines of the feed-off-thearm type such as disclosed in U. S. Patent No. 1,741,095, granted to Norman V. Christensen and Harold J. LeVesconte on December 24 1929.

The chief aim of our invention is to simplify the construction of looper mechanisms for sewing machines with a view toward attaining greater compactness, minimizing vibration so that higher speeds may be maintained, and increased production secured from the machines, and to insure against easy derangement of the coacting parts incident to high speed operation.

In looper mechanism having the above attributes it is a further aim of our invention to render the action of looper or loopers positive through provision of a simplified and improved form of spreader means to cooperate with said looper or loopers.

Another object of our invention is to provide a simplified form of lochng means whereby the loopers are releasably secured to the looper shaft with capacity for being moved to a retracted position for convenience of ready threading.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein Fig. I is a side elevation of a feed-ofi-the-arm sewing machine incorporating our improved looper mechanism, a portion of the machine frame having been broken out to expose parts of the mechanism at the interior.

Fig. II is a longitudinal sectional view through the work-supporting arm of the machine.

FigaIII is a view of the Work-supporting arm partly in plan and partly in section taken as indicated by the arrows III--III in Figs. I and II, with its cover plates removed to expose the feeding and looper mechanisms within the hollow of the work-supporting arm.

Fig. IV is a longitudinal fragmentary sectional view of the front end of the work-supporting arm drawn to an enlarged scale.

Fig. V is a cross sectional view of the worksupporting arm taken as indicated by the arrows V-V in Figs. 11 and 1V.

Fig. VI is a detail sectional view corresponding to Fig. V showing the locking means for the looper in position to release the latter.

Fig. VII is a fragmentary plan section taken as indicated by arrows VII-VII in Fig. II.

Figs. VIII and IX are fragmentary detail sectional views taken as respectively indicated by the arrows VIII-VIII and IXIX in Fig. II.

Fig. X is a perspective view of the front end of the looper shaft; and

Fig. XI is a perspective View of one of the elements of the locking means for the loopers.

The feed-off-the-arm sewing machine herein illustrated for convenience of exemplifying the looper mechanism of our invention has a frame 1 with an elevated longitudinally-extending laterally projecting tubular portion 2 integrally formed with a supporting base 3. Suitably journaled within the tubular portion 2 of the machine frame I is a drive shaft 4 to the protruding front end of which is secured a combined hand and belt wheel 5 whereby it may be driven either manually or by power. Extending laterally from the tubular elevated portion 2' of the frame I near the front of the machine is a head 6 which is underreached by the free end of a hollow horizontal work-supporting arm I which at its rean end has an upward bend B joined to a complemental downward bend 9 of the tubular portion 2 of the frame with attendant formation of a vertical connecting hollow l0. Guided for endwise reciprocation in the head 6 and actuated through suitable connections (not shown) from the drive shaft 4 is a vertical needle bar I I carrying a pair of needles 12. Also confined to up and down movement in the head 6 is a presser bar 13 whereto a presser foot i4 is secured at the lower end. The feed mechanism of the machine includes a feed dog 15 which has teeth projecting up through an opening 16 in the throat plate H at the free end of the work supporting arm, and which bridges an opening 18 at the corresponding end of a feed bar l9 extending longitudinally of the hollow of said work-supporting arm. As shown in Figs. 11 and III the feed bar 19 has guidance adjacent its front end in an upwardlyopen slot 20 of a web or partition 2! extending crosswise of the work-supporting arm. Immediately rearward of the partition 21 the feed bar 19 is supported by a pair of upright links 22 whereof the lower ends are pivotally connected to the horizontal arm 23 of a bell crank member 25. As shown the bell crank member is mounted for oscillation about the eccentric portion 26 of a rotatively-adjustable pin 21 engaged at opposite ends in lugs 28 at the interior of the work-supporting arm. Lift movements are imparted to the feed bar 19 from a rotary eccentric actuator 29 (Fig. I) on the drive shaft l whereof the strap rod 30 is connected at its lower end to the horizontal arm ll of another bell crank member 82 mounted to oscillate on a pin 83 extending crosswise between the sides of the work-supporting arm I. The pendant arm 34 of the bell crank member 32 is coupled by means of a horizontal link 35 with the upstanding arm 36 of the bell crank lever 25. Back and forth or feed movements are induced in the feed bar by another rotary eccentric actuator 31 (Fig. I) on the drive shaft 4 whereof the strap rod 88 is connected at its lower end to the horizontal arm 39 (Fig. 111) of a third bell crank lever 46 which is free on another cross shaft 4| in the rear end of the work-supporting arm I the pendant arm 42 of the bell crank lever being pivotally connected directly to the rear end of the feed bar. The illustrated feed mechanism constitutes, per se, the subject matter of a separate patent application, Serial Number 149,593 filed by us concurrently herewith.

The looper mechanism with which the present invention is more especially concerned includes a pair of loopers 45 which are arranged to cooperate with the needles |2 beneath the throat plate II in the clearance opening |8 provided at the front end of the feed bar 9. By suitable means later on described, the loopers 45 are supported forwardly of the needles at the front end of a. shaft 46 extending longitudinally through the hollow of the work supporting arm I at a level below the feed bar I9, said shaft being journaled at its rear end in a bushing 41 fixed within a boss 48 at the interior of said worksupporting arm. For the greater part of its length, the shaft 46 is surrounded by a sleeve 49, and adjacent its front end is journaled in a bushing 58 (Figs. II and IV) within a short coaxial supplemental sleeve 5| secured to the forward end of the sleeve 49, said supplemental sleeve 5| being in turn joumaled in a bearing bushing 52 fixed in the cross web or partition 2| interiorly of the work supporting arm 1. At its rear end, the sleeve 49 is journaled in a bushing 53 fixed in an upstanding bearing lug 54 within the work supporting arm at a point intermediate the length of the latter.

During the operation of the machine, the looper shaft 46 is rocked and reciprocated endwise in its bearings for impartation of loop taking and needle avoiding movements to the loopers 45. The looper shaft 46 derives its rocking movement from a rotary eccentric actuator 55 (Fig. I) on the drive shaft 4 whereof the strap rod 56 is connected at the lower end to a ball head 51 of a crank arm in the form of a screw stud 58 threadedly engaged in a clamp collar 59 on the shaft near the rear end of the latter, see Figs. VII, and VIII. By adjusting the stud 58 in the collar 59, the swing imparted to the looper shaft 46 may be increased or decreased as may be required. A jam nut 68 serves to prevent accidental rotation of the stud 58 in adjusted positions. Endwise movements are induced in the looper shaft 46 by another rotary eccentric actuator 6| (Fig. I) on the drive shaft 4, the strap rod 62 of the latter being connected at its lower end to the horizontal arm 63 of a bell crank lever 64 which is free to swing on the cross pin 4| hereinbefore referred to. The pendant arm 65 of the bell crank lever 64 is in turn coupled, by means of a short link 66. with a stud 61 projecting laterally from a collar 68 on the shaft 46. The collar 68 is free to oscillate but held against relative actual displacement in the interval between the clamp collar 58 and another collar 69 secured to the looper shaft. As shown, the strap rod 62 is provided at its opposite ends with right and left hand screw threads which will allow for adjustment to position the longitudinal axis of the looper path properly with respect to the needle path so that proper cooperation between the loopers 45 and the needles I! is attained.

Beyond a circumferential flange 16, the front end of the looper shaft 46 is diametrically enlarged and provided with a longitudinal slot as at H (see Fig. X) within which the horizontal portion of an angular looper holder arm 12 is received. In order to render the loopers 45 accessible for ready threading, the holder arm 12 is swingable downward about a pin 13 extending crosswise of the slot H, from the normal position shown in Fig. II to the retracted position shown in Fig. IV upon removal of a detachable closure cap 14 from the end of the work supporting arm I of the machine. The looper holder arm 12 is normally locked in its raised or active position by a keeper collar 15 (shown in perspective in Fig. XI) which is rotatable on the slotted end portion ll of the looper shaft 46. As shown, the collar 15 has a knurled head 16 whereby it can be manipulated and turned from the position of Fig. V to that of Fig. VI to bring a longitudinal slot 'I'l thereof into registry with the slot II in the end of the looper shaft and thereby enable downward swinging of the looper holder arm as above explained, the latter movemen being effected automatically by a spring finger 18 which is anchored in the front end of said collar and which normally presses outwardly upon the shank of the looper. A retaining ring 19 (Fig. IV) with turned circumferential flanges 80, 8| which respectively lap the. flange 10 of the shaft 46 and the circumferential flange 82 of the locking collar, holds the latter assembled with said shaft and prevents endwise shifting thereof on said shaft. Upon upward swinging of the looper holder arm 12 to its normal position, a coiled torsion spring 83 within the hollow of the retaining ring 19 acts to automatically turn the collar back to its looking position as shown in Fig. V, one end of said spring being aiiixed to said collar and the other to the circumferential flange 10 of the shaft as shown in Fig. IV. The loopers 45 are secured to the holder 12 with provision for independent up and down adjustment by cap screws 85 which pass through longitudinal slots 86 in the downward shanks 81 of said loopers as instanced in Figs. 11 and IV.

Incident to coaction with the loopers 45, the needles I2 are guided and steadied by a guard 88 located within the hollow of the work-supporting arm and projecting upward into the Opening I8 in the feed bar. As shown in Fig. V, the guard 88 is secured by a screw 89 and provided with laterally-spaced vertical grooves 98 in its front face to receive said needles.

Disposed rearwardly of the path of the needles l2 and arranged to cooperate with the loopers 45 is a laterally oscillating spreader 9| which reaches over the needle guard 88 above the loopers within the opening at the front end of the feed bar 9, see Figs. III and IV. As shown, the spreader 9| has a downward shank 92 secured by screws 93 to an upward projection 94 of the short supplemental sleeve 5| affixed, as hereinbefore described, to the forward end of the sleeve 49 which surrounds the looper shaft 46. At its free end, the spreader 9| is provided with laterally spaced substantially vertical notches 9|a (Figs.

IIIV) which are adapted to engage the bights of the looper threads (not illustrated) extending from the eyes of the loopers 45 and the previous 1y formed stitches to spread them away from the bodies of said loopers and thereby insure entry of the loops thus defined by the needles I2 as the latter descend. From Figs. II and VII, it will be noted that the sleeve 49 is prevented from shifting endwise by collars 95 and 96 aflixed thereto and respectively abutting opposite ends of the bearing bushing 53 in the interior lug projection 54 of the work supporting arm I. As further shown in Figs. VII and IX, the collar 96 has a.

ily adapted, by increasing or decreasing the number of needles and loopers, for the production of single rows ofstitches or to form a seam with more than two rows. Or again, it may be ar ranged to produce a seam with connected multiple rows of stitches such as featured in U. S. Patents Nos. 883,614 and 1,934,328, granted respectively to Stockton Borton on March 31, 1908, and to Charles F. Rubel on November '7, 1933.

Having thus described our invention, we claim:

1. Looper mechanism for sewing machines comprising a looper shaft with a longitudinallyslotted portion; a looper holder arm pivotally connected within the slot of the shaft to enable swinging of the looper from its normal active position to a retracted position for convenience of threading it; and a longitudinally-slotted collar surrounding the slotted portion of the shaft and a portion of the looper holder arm to normally lock the latter in its active position, said collar being rotatable so that its slot can be brought into registry with the slot in the shaft to permit retraction of the looper as aforesaid.

2. Looper mechanism for sewing machines including a looper shaft with g a longitudinallysl otted portion; a looper holder arm pivotally connected within the slot of the shaft to enable swinging of the looper from its normal active position to a retracted position for convenience of threading it; a longitudinally-slotted collar surrounding the slotted portion of the shaft and a portion of the looper holder arm to normally look the latter in its normal position, said collar being rotatable so that its slot can be brought into registry with the slot in the shaft to permit retraction of the looper as aforesaid; and spring means to yieldingly resist rotation of the locking collar about the shaft incident to releasing the looper holder arm.

3. Looper mechanism for sewing machines including a looper shaft with a longitudinal slotted portion; a looper holder arm pivotally connected within the slot of the shaft to enable swinging of the looper from its normal active position to a retracted position for convenience of threading it; a longitudinally-slotted collar surrounding the slotted portion of the shaft and a portion of the looper holder arm to normally look the latter in its active position, said collar being rotatable so that its slot can be brought into registry with the slot in the shaft; and spring means operative to automatically swing the looper holder arm to retracted position upon rotation of the locking collar as aforesaid.

4. The combination in a sewing machine having a throat plate, and a needle operated from above the throat plate; of looper mechanism including a horizontal looper operative from one side of the path of the needle below the throat plate, and a spreader operative from the other side of the needle below the throat plate and swinging in a plane above the looper.

5. The combination in a sewing machine having a throat plate, a needle operated from above the throat plate and a needle guard to guide and brace the needle below the throat plate; of looper mechanism including a looper operative from one side of the path of the needle below the throat plate and movable over the needle guard, and a cooperating spreader operative from the other side of the path of the needle below the throat plate and also movable over said needle guard.

6. The combination in a sewing machine having a throat plate, a needle operated from above the throat plate, a feed dog operating upwardly through the throat plate, and a feed bar with an opening bridged by the feed dog; of looper mechanism including a looper and a spreader adapted to cooperate with the needle below the throat plate and within the opening of the feed bar, and means for actuating said looper and spreader.

7. The combination in a sewing machine having a throat plate, a needle operated from above the throat plate, a feed dog operating upwardly through the throat plate, a feed bar with an opening bridged by the feed dog, and a needle guard projecting upward into the opening in the feed bar; of looper mechanism including a looper forward of the needle guard and adapted to move in a plane above said needle guard within the opening of the feed bar, and means for actuating the looper.

8. The combination in a feed-off-the-arm sew ing machine having a work supporting arm with a throat plate at the free end thereof, a needle operated from above the throat 'plate, a feed dog operating upwardly through the throat plate, a feed bar extending longitudinally of the work support and having an opening at its front end bridged by the feed dog, and a needle guard projecting upwardly into the opening in the feed bar; of looper mechanism including a looper supported forward of the needle guard and operative in a plane above said needle guard, a spreader supported rearward of the needle guard and operative in a plane above the looper, and means for respectively actuating said looper and spreader.

9. The combination in a feed-off-the-arm sewing machine having a work supporting arm with the throat plate at the free end thereof, a needle operated from above the throat plate, a feed dog operating upwardly through the throat plate, and a feed bar extending longitudinally of the work support and having an opening at its front end bridged by the feed dog; of looper mechanism including a looper, a shaft extending longitudinally of the work supporting arm below the feed bar, a holder connected to the front end of the shaft and supporting the looper forward of -the needle for cooperation with the latter below the throat ,plate within the opening of the feed bar; and means for oscillating and axially reciprocating the looper shaft to impart loop takmg and needle avoiding movements to the looper.

10. The combination in a feed-ofl-the-arm sewing machine having a frame with an elevated longitudinal portion, and a work supporting arm with its 'free end underreaching a head on said elevated portion, a needle bar with a needle confined to vertical reciprocation in the head, a feed dog operating upwardly through a throat plate at the front end of the work supporting arm, and a drive shaft extending longitudinally of the elevated portion of the machine frame; of looper mechanism including a shaft extending longitudinally of the work supporting arm, a looper at the front end of the shaft forward of the needle to cooperate with the latter below the throat plate, a second shaft extending longitudinally of the work support, a spreader on the latter shaft rearward of the needle to cooperate with the looper, and separate means on the drive shaft connected respectively to the looper shaft and to the spreader shaft to impart rocking and endwlse reciprocatory movements to said looper shaft and to impart oscillatory movement to said spreader shaft.

11. The combination in a feed-ofl-the-arm sewing machine having a frame with an elevated longitudinal portion, and a work supporting arm with its free end underreaching a head on said elevated portion, a needle bar with a needle confined to vertical reciprocation in the head, and a horizontal drive shaft journaled on said elevated frame portion; of looper mechanism including a shaft extending longitudinally of the work supporting arm, a looper at the front end of the shaft forward of the needle to cooperate with the latter below a throat plate at the corresponding end of said work supporting arm, a sleeve surrounding the looper shaft, a spreader on the sleeve rearward of the needle adapted to cooperate with the looper, and separate means on the drive shaft respectively connected to the looper shaft and to the sleeve for imparting rocking and endwise reciprocatory movements to said looper shaft, and oscillatory movements to said sleeve.

12. Looper mechanism for sewing machines having a needle and a work support, said mechanism including a pair of coaxial shafts, a thread carrying looper mounted on one of the shafts, a cooperating spreader mounted on the other shaft with its thread engaging end extending between the work support and the thread carrying end of the looper, means for oscillating and for axially reciprocating the looper shaft to impart loop taking and needle avoiding movements to the looper, and means for oscillating the other shaft only to cause the spreader to engage and distend the looper thread between the looper and the last formed stitch for subsequent passage of the needle thread loop between the distended looper thread and the looper.

13. Looper mechanism for sewing machines ac-- cording to claim 12, in which one of the shafts is in the formvof a sleeve and surrounds the other shaft,

14. Looper mechanism for sewing machines according to claim 12, in which the shaft which carrice the spreader is in the form of a sleeve surrounding the looper shaft.

15. Looper mechanism for sewing machines including a work support, a four motion thread carrying looper, means for imparting straight line loop taking and shedding movements and a lateral rocking needle avoiding movement to the looper, a spreader with its thread engaging end extending between the work support and the thread carrying end of the looper, and means for oscillating the spreader in a path parallel to the needle avoiding movement of the looper about the oscillating axis of the latter to engage and distend the looper thread between the eye of the looper and the last formed stitch for subsequent passage of a needle thread loop between the distended looper thread and the looper.

16. Looper mechanism for sewing machines according to claim 12 in which the spreader shaft is in the form of a sleeve surrounding the looper shaft and the looper is mounted on one end of its shaft protruding from the sleeve with its thread carrying end extending rearward, and wherein the spreader is mounted on the corresponding end of the sleeve with its thread engaging end extending forward toward the looper.

HANS HACKLANDER. GEORGE SAUER. 

